1. Technical Field
The present disclosure relates to a centrifugal compressor that compresses a fluid (gas, such as air, is included) utilizing a centrifugal force and, in particular, to a diffuser in the centrifugal compressor.
2. Description of the Related Art
In recent years, various research and development of a centrifugal compressor used for a turbocharger, a gas turbine, an industrial air facility, etc. have been conducted (refer to Japanese Patent Laid-Open Publication Nos. 2009-2305, 2006-220053, and 2010-196542).
A general centrifugal compressor includes a housing. The housing has a shroud thereinside. In the housing, a wheel (an impeller) is rotatably provided around an axial center thereof. The wheel includes a disk. A hub surface of the disk extends from one side in an axial direction toward an outside in a radial direction of the turbine wheel. On the hub surface of the disk, a plurality of blades is integrally provided spaced apart from each other in a peripheral direction. A tip edge of each blade extends along the shroud of the housing.
An annular diffuser (a diffuser flow passage) that decreases a velocity of a compressed fluid (a compression fluid) to thereby raise a pressure thereof is formed on an outlet side of the wheel in the housing. In addition, a scroll (a scroll flow passage) that communicates with the diffuser is formed on an outlet side of the diffuser in the housing.